Introducer sheaths are frequently used to percutaneously insert guide wires, catheters and similar elongated cylinders into arteries or veins (collectively called vessels) of the human body. All such sheaths are made in one piece which precludes leaving a distal portion in the vessel while removing or changing the proximal portion that lies outside of the human body.
Furthermore, recent advances in medical techniques for removing thrombus from blood vessels involve the use of a suction catheter percutaneously inserted through an introducer sheath to hold onto a thrombus by the use of suction at the catheter's distal end. However, when the thrombus is pulled into a one-piece sheath, the valve at the sheath's proximal end must be forcibly removed before the thrombus can be pulled completely out of the sheath. This is difficult to do and typically results in considerable blood loss through the sheath's proximal end when the valve is removed.